The present invention relates to an outboard motor in which a throttle valve equipped on an outboard motor main body is driven to be opened and closed from a throttle operation unit in a cockpit of a boat via a long throttle cable.
Conventionally, when an outboard motor is mounted to the hull of a boat, a distance from the cockpit to the engine becomes long in comparison with an engine unit for a motorcycle or engine unit for an automobile. In general, a throttle valve (a throttle body, a carburetor) equipped on the outboard motor is designed to be operated and driven (to be opened and closed) from a throttle operation unit (a remote control box) in the cockpit of a hull via a throttle cable which is 5 meters or longer.
The throttle cable is in general constituted by an outer cable and an inner cable which is slidably inserted through the outer cable, and the sliding resistance between the outer cable and the inner cable changes depending on the length of the throttle cable and the number of bends along the length of and curvature of the throttle cable.
In the case of the outboard motor, as has been described above, since the throttle cable is long and is laid out in a bent fashion within the hull, the sliding resistance is increased. In addition, since the inner cable extends, the hysteresis in the throttle opening and closing directions becomes large and there is caused difficulty in fine adjustment of throttle opening.
With the outboard motor, from the aforesaid reason, there is caused a problem that the throttle lever has to be operated a plurality of times in order to make adjustments required to open and close the throttle properly to have a desired boat velocity (engine speed).